PCIe is a high-speed serial computer expansion bus standard. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism and native hot-plug functionality. Hot-plug functionality or hot-plugging is a term used to describe the functions of replacing computer system components without shutting down the system. With hot-plugging it is possible to add components to expand a system without significant interruption to the operation of the system. Once appropriate software is installed, a user can plug and unplug the components without rebooting the system. A well-known example of this functionality is the Universal Serial Bus, USB that allows users to add or remove peripheral components such as a mouse, keyboard, or printer.
Recent development in PCIe hardware, i.e. PCIe over fiber allows placing connected elements at distant locations, e.g in different cabinets or even in different rooms/floors of a building. Hot-plugging over a distance to a remote node had previously not been possible. The new development of the existing PCIe standard prescribes that any hot-plug operation shall be initiated by a manual operation, i.e. a button press by the operator. Consequently, if an operator wants to configure or reconfigure (plug/unplug) the remote end of a fiber cable, the operator has to visit both ends of the fiber cable in order to perform the manual operation. Alternatively, the manual operation requires two operators connected by other means such that they can communicate with each other, eg. by cellular telephone.
A more thorough description of the PCIe standard and hot-plugging may be found in “PCI Express Base Specification, Revision 3.0”, “PCI Hot-Plug Specification, Revision 1.1” and “PCI Standard Hot-Plug Controller and Subsystem Specification, Revision 1.0”.
As mentioned above recent developments allow placing connected elements at a distant location. However, currently existing standards and solutions do not suggest any solutions for dealing with hot-pluggable components at a distant location, i.e. physically separated from a hot-plug controller of an uplink port.